Passive solar is the use of the sun’s energy directly for either heating or cooling purposes.
Unlike photovoltaic or other technological solar power applications, passive solar does not involve energy gathering or transformation through mechanical or electronic means. There are many varied approaches to passive solar. Most commonly it is used for home heating, but it is also being applied in the datacenter.
The principles behind passive solar may be applied in construction of a home as with integrated solar or applied as later upgrades. Examples of built in passive solar features include south facing windows, dark floors (often stone) to collect and store heat as a thermal mass for release during cooler times. Examples of additions one can make to existing buildings include passive heaters made from downspouts, aluminum cans, aluminum screening and other often recycled materials.
Passive solar means of heating has had much of their support and creation through the drive for sustainability by individuals and businesses.
See a video illustration of passive solar: